.\"	$OpenBSD: presto.4,v 1.6 2013/06/04 21:05:53 miod Exp $
.\" Copyright (c) 2003, Miodrag Vallat
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.Dd $Mdocdate: June 4 2013 $
.Dt PRESTO 4 sparc
.Os
.Sh NAME
.Nm presto
.Nd Prestoserve battery-backed memory
.Sh SYNOPSIS
.Cd "presto* at sbus?"
.Cd "presto* at mainbus?" Pq "SS10/SS20 NVSIMM"
.Sh DESCRIPTION
The
.Tn Legato
Prestoserve NVRAM SBus cards and NVSIMM used to be part of the
.Dq NFS accelerator
product, which used the device's memory as an NFS-dedicated cache, increasing
performance of NFS servers exporting filesystem as NFS protocol, version 2.
.Pp
The
.Nm
driver does not attempt to achieve such a behaviour, which is questionable
with the advent of NFS protocol, version 3.
.Pp
Instead, it will provide direct access to the NVRAM, as a block device.
.Sh FILES
.Bl -tag -width /dev/rprestoXXXXX -compact
.It Pa /dev/presto Ns Ar u Ns Ar p
block mode Prestoserve card number
.Ar u ,
partition
.Ar p
.It Pa /dev/rpresto Ns Ar u Ns Ar p
raw mode Prestoserve card number
.Ar u ,
partition
.Ar p
.El
.Sh SEE ALSO
.Xr intro 4 ,
.Xr disklabel 5 ,
.Xr disklabel 8 ,
.Xr MAKEDEV 8
